The present application relates generally to paging network architecture and operation and more particularly to two-way paging.
Two-way paging systems that allow the individual subscriber to transmit responses are becoming more and more prevalent. For example, a recent pager product from Motorola of Schaumburg, Ill., the Tango.TM. pager product, allows one to address a message to a particular pager subscriber unit and specify within the message multiple possible responses. The user of the subscriber unit then selects a response which is returned to the message sender.
Power consumption within a two-way pager subscriber unit presents a problem because transmitter operation inherently consumes far more power than receiver operation alone. Even modest transmitter power output levels require either large batteries, making the whole unit less compact and convenient, or very short battery life, necessitating frequent battery changes.
FIG. 1 depicts a prior art two-way paging network infrastructure developed to address the problem of pager power consumption. FIG. 1 depicts elements of a paging network 100 operating within a circular region 102. A transmitter site 104 sends messages to individual two-way pager units 106 within region 102. However, to save on power consumption, individual pager units 106 do not have sufficient transmitter power to reach transmitter site 104 with their responses. Accordingly, paging network 100 also includes a plurality of paging receiver sites 108 for receiving transmissions from individual pager units 106, effectively representing a microcellular system for receiving pager responses and registration messages. Each such paging transmitter site 104 covers a region having a diameter of 20 miles. Each such paging receiver site 108, however, covers a region covering only 20% of the area covered by paging transmitter site 104.
The need for numerous closely spaced paging receiver sites greatly complicates the construction and maintenance of the paging network infrastructure. Particularly in crowded urban areas, site acquisition is an expensive and cumbersome process. Also, the receiver sites must all be maintained independently. What is needed is a paging infrastructure that supports low-power capabilities but with reduced infrastructure construction and maintenance costs. SUMMARY OF THE INVENTION
The present invention provides, e.g., a substitute for the uplink infrastructure associated with typical two-way paging protocols. Instead of employing a microcellular arrangement of paging receiver sites, wherein each cell is served by its own receiver site, the present invention contemplates servicing multiple cells from a single receiver site. The operation of the protocol need not be modified. A region surrounding the single receiver site is divided into angular sectors. Each angular sector has an associated beam of a multi-element antenna array. The sectors represent the cells used for the up-link in prior art two-way pager infrastructure. This approach substantially reduces the cost of constructing and operating a two-way pager infrastructure.
In accordance with a first aspect of the present invention, a method for operating the uplink portion of a two-way paging network includes steps of: providing a plurality of receivers at a receiver site, each of the receivers coupled to a selected beam of a plurality of beams of a multi-element antenna array, the plurality of beams dividing a region surrounding the receiver site into sectors reached by individual ones of the plurality of beams, and employing the receivers to receive messages transmitted from a plurality of pagers via the plurality of beams.
In accordance with a second aspect of the present invention, a receiver system in a two-way paging network includes: a plurality of receivers at a receiver site, and a beamforming network. Each output of the beamforming network is coupled to one of the plurality of receivers. Each input of the beamforming network is coupled to an element of a multi-element antenna array. Each of the receivers is coupled to a selected beam of a plurality of beams of the multi-element antenna array. The plurality of beams divide a region surrounding the receiver site into sectors reached by individual ones of the plurality of beams.
A further understanding of the nature and advantages of the inventions herein may be realized by reference to the remaining portions of the specification and the attached drawings.